To create a new account inside WHM follow these steps:

Creating a Package

Before you can create a cPanel account, you will need to create a package for it.

1. Log in to WebHost Manager (WHM) using your username and password at http://yourdomain.com:2087, where yourdomain.com is your website address.
2. Search and Click on the Add a Package tool in WHM.
3. Add the Package Name and set the settings for this package. Click Add to add the package. 
Note 1: You normally only need to focus on the Disk Quota and Monthly Bandwidth limits, as they'll relate to your plan's total usage limits. Others can be set to unlimited or left as default.

Creating the cPanel Account

1. Log in to WebHost Manager (WHM) using your username and password at http://yourdomain.com:2087, where yourdomain.com is your website address
2. Once logged into your account locate the 'Account Functions' tab
3. Once you have navigated into the Account Functions select 'Create a New Account'
4. Add the Domain Information, select the Package and other Settings then click create.

This will give you access to create a new account on your reseller plan.